The U.S. Environmental Protection Agency on June 30 released peer-reviewed results from the first round of its own independent toxicity testing on eight oil dispersants, which indicated that none of the eight dispersants tested, including the product in use in the Gulf of Mexico, displayed biologically significant endocrine disrupting activity.

While the dispersant products alone – not mixed with oil – have roughly the same impact on aquatic life, JD-2000 and Corexit 9500 were generally less toxic to small fish and JD-2000 and SAF-RON GOLD were least toxic to mysid shrimp. While this is important information to have, additional testing is needed to further inform the use of dispersants.

"We will continue to conduct additional research before providing a final recommendation," said EPA Administrator Lisa P. Jackson. "We want to ensure that every tool is available to mitigate the impact of the BP spill and protect our fragile wetlands. But we continue to direct BP to use dispersants responsibly and in as limited an amount as possible."

EPA said it continues to carefully monitor BP’s use of dispersant in the Gulf. Dispersants are generally less toxic than oil and can prevent some oil from impacting sensitive areas along the Gulf Coast. EPA believes BP should use as little dispersant as necessary and, on May 23, Jackson and then-Federal On-Scene Coordinator Rear Admiral Mary Landry directed BP to reduce dispersant usage by 75 percent from peak usage. EPA and the Coast Guard formalized that order in a directive to BP on May 26. Over the next month BP reduced dispersant use 68 percent from that peak.

The agency also directed BP to analyze potential alternative dispersants for toxicity and effectiveness. BP reported that it was unable to find a dispersant that is less toxic than Corexit 9500, the product currently in use. Following that, EPA began its own scientific testing of eight dispersant products on the National Contingency Plan Product Schedule. Those dispersant products are: Dispersit SPC 1000, Nokomis 3-F4, Nokomis 3-AA, ZI-400, SAF-RON Gold, Sea Brat #4, Corexit 9500 A and JD 2000.

The next phase of EPA’s testing will assess the acute toxicity of multiple concentrations of Louisiana Sweet Crude Oil alone and combinations of Louisiana Sweet Crude Oil with each of the eight dispersants for two test species.